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Histology of Sclerotium cepivorum infection of onion roots and the spatial relationships of pectinases in the infection process

journal contribution
posted on 2023-05-16, 11:48 authored by Dean Metcalf, Calum WilsonCalum Wilson
Sclerotium cepivorum (isolate Sc4) hyphae penetrated the epidermis and hypodermis of onion roots and grew into the cortex. Immediately following penetration only the cells through which S. cepivorum grew were lysed, but subsequently cells were killed and cell walls disintegrated ahead of the infection hyphae. Sclerotium cepivorum produced two polygalacturonases (PG) and two pectinesterases (PE) in culture. These isozymes were also found in infected onion root tissues and another PG and a PE were occasionally detected. Two isozymes of PG and three isozymes of PE diffused ahead of the infection hyphae. The spatial distribution of these enzymes was associated with cell death and cell wall degradation. The epidermis, hypodermis, endodermis and vascular tissues were more resistant to hydrolysis than the cortex, but only the endodermis and cells within it retained nuclei following hydrolysis of the surrounding cortical tissues. The cavity within the root cortex became filled with swollen, vacuolate S. cepivorum hyphae.

History

Publication title

Plant Pathology

Volume

48

Issue

4

Pagination

445-452

ISSN

0032-0862

Department/School

Tasmanian Institute of Agriculture (TIA)

Publisher

Blackwell Science

Place of publication

Edinburgh, UK

Repository Status

  • Restricted

Socio-economic Objectives

Field grown vegetable crops

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